1. Field of Invention
The present invention relates to a full-screen 3D image display device, which provides a dynamic liquid crystal parallax barrier device for solving a 3D image resolution deterioration problem caused by view separation of a multi-view 3D image displayed by a conventional parallax barrier, and achieves the purpose of displaying a multi-view 3D image with a full-screen image resolution through a multi-view image dynamic combination and display procedure and a barrier electrode dynamic driving procedure.
2. Related Art
FIG. 1 to FIG. 3 are schematic views of structure of three types of parallax barriers in the prior art. FIG. 1 is a schematic view of a vertical strip parallax barrier in the prior art, FIG. 2 is a schematic view of a slant-and-strip parallax barrier in the prior art, and FIG. 3 is a schematic view of a slant-and-step parallax barrier in the prior art. The basic optical structures of the vertical strip parallax barrier 10, the slant-and-strip parallax barrier 20, and the slant-and-step parallax barrier 30 include light-transmissive elements 11, 21, 31 and shielding elements 12, 22, 32 respectively. The relevant principles of the three types of parallax barriers, the designs and optical functions of the parallax barrier structures, and the construction of the multi-view 3D image may refer to the paper “Theory of Parallax Barriers”, Sam H. Kaplan, Vol. 59, Journal of the SMPTE, 1952, and may refer to ROC Patent Application No. 097135421, No. 098113625, and No. 098128986 for details.
In general, the parallax barrier may be fabricated by using a liquid crystal panel technique, and after driven by a voltage, the optical effect of the light-transmissive elements 11, 21, 31 and the shielding elements 12, 22, 32 can be achieved.
FIG. 4 is a schematic view of structure of a liquid crystal parallax barrier in the prior art. The liquid crystal parallax barrier 50 mainly consists of two linear polarizers 51, two transparent substrates 52 (for example, glass), a common electrode layer 53, a barrier electrode layer 56, two alignment layers 54, and a liquid crystal molecular layer 55. The structure of the liquid crystal parallax barrier in the prior art may refer to U.S. Pat. No. 5,315,377. The liquid crystal molecular layer 55 generally adopts a TN liquid crystal material. The two linear polarizers 51 respectively have a light polarization direction and both polarization directions are perpendicular to each other. The common electrode layer 53 and the barrier electrode layer 56 are transparent electrodes formed by ITO (referred to as electrodes for short hereinafter). An electrode structure 57 of the barrier electrode layer 56 is formed by a barrier structure including a vertical strip parallax barrier, a slant-and-strip parallax barrier, or a slant-and-step parallax barrier. When a voltage between the electrode structure 57 and the common electrode layer 53 is 0, all the liquid crystal molecules of the liquid crystal molecular layer 55 are in a spiral configuration, which allows all the incident light 58 to penetrate through the liquid crystal parallax barrier 50 (definitely, the light transmittance of the above elements is not 100 percent, and the incident light is somewhat absorbed). Therefore, the liquid crystal parallax barrier 50 is in a transparent state.
As shown in FIG. 5, when a proper driving voltage v (which can be a square wave electrical signal having a proper amplitude and period) is applied between the electrode structure 57 and the common electrode layer 53, the liquid crystal molecules between the electrode structure 57 and the common electrode layer 53 are in an upright configuration, thereby achieving the effect of shielding the incident light 58 (in the following illustration, when the electrode structure is marked by the black color, it indicates that the electrode has a light shielding effect). Therefore, the electrode structure 57 becomes the shielding element of the parallax barrier, and the region outside the electrode structure 57 is regarded as the light-transmissive element of the parallax barrier. As such, under the control of the external driving voltage, the liquid crystal parallax barrier in the prior art may achieve the 2D/3D switching effect.
As described above, the optical functions of the light-transmissive elements 11, 21, 31 and the shielding elements 12, 22, 32 perform the view separation on a multi-view 3D image (which is a full-screen multi-view 3D image formed by the combination of a plurality of single-view images with the parallax effect) displayed on a screen at an optimal viewing position on an optimal viewing distance. That is, the single-view image is presented at the respective optimal viewing position. However, the image resolution of the separated single-view image is deteriorated with the increase of the number of views, and finally the deterioration of the 3D image resolution occurs. For simplifying illustration, the vertical strip parallax barrier and the double-view image are adopted for illustrating the deterioration of the single-view image resolution after separation.
FIG. 6 is a schematic view of the consisting of a full-screen image in the prior art. As shown in FIG. 6, the full-screen image 70 is a display frame of a common flat panel display screen, which is formed by M×N R, G, B sub-pixel images Vi,j, where i and j are the indices representing respectively vertical and horizontal positions of the sub-pixel image Vi,j and i=0 to M−1, j=0 to N−1. Therefore, a mathematical expression
      ∑          i      =      0              M      -      1        ⁢            ∑              j        =        0                    N        -        1              ⁢          V              i        ,        j            is used to indicate the consisting of the full-screen image 70. In addition, the R, G, B sub-pixels may be configured along the horizontal direction or the vertical direction.
FIG. 7 is a schematic view of the consisting of a left-view image before the combination of a double-view image. The left-view image 71 is a full-screen image formed by M×N R, G, B sub-pixel images V0i,j. FIG. 8 is a schematic view of the consisting of a right-view image before the combination of a double-view image. The right-view image 72 is a full-screen image formed by M×N R, G, B sub-pixel images V1i,j.
FIG. 9 is a schematic view of the consisting of a double-view combined image. As shown in FIG. 9, the left-view image 71 and the right-view image 72 are combined in a vertical interlacing manner to form a full-screen double-view combined image 73. That is to say, the full-screen image is obtained by inserting at the positions of the even-numbered columns the images V0i,2n at the positions of the even-numbered columns of the left-view, and inserting at the positions of the odd-numbered columns the images V1i,2n+1 at the positions of the odd-numbered columns of the right-view. Therefore, the structure of the double-view combined image 73 is expressed by the following formula:
                                          Σ            0                    ⁡                      (            t            )                          =                              ∑                          i              =              0                                      M              -              1                                ⁢                                    ∑                              n                =                0                                                              int                  ⁡                                      (                                          N                      /                      2                                        )                                                  -                1                                      ⁢                          [                                                V                  0                                      i                    ,                                          2                      ⁢                      n                                                                      +                                  V                  1                                      i                    ,                                                                  2                        ⁢                        n                                            +                      1                                                                                  ]                                                          (        1        )            
where t is time, n is an integer from 0 to int(N/2)−1, and int is a rounding function.
In addition, regarding the slant-and-strip parallax barrier and the slant-and-step parallax barrier, the double-view combined image can be expressed by the following formula:
                                          Σ            0                    ⁡                      (            t            )                          =                              ∑                          i              =              0                                      M              -              1                                ⁢                                    ∑                              n                =                0                                                              int                  ⁡                                      (                                          N                      /                      2                                        )                                                  -                1                                      ⁢                          [                                                V                  0                                      i                    ,                                                                  2                        ⁢                        n                                            +                                              Mod                        ⁡                                                  (                                                      i                            /                            2                                                    )                                                                                                                    +                                  V                  1                                      i                    ,                                                                  2                        ⁢                        n                                            +                                              Mod                        ⁡                                                  (                                                                                    i                              +                              1                                                        2                                                    )                                                                                                                                ]                                                          (        2        )            
where Mod is a remainder function.
FIG. 10 is a schematic view of a separation function on a double-view combined image. As shown in FIG. 10, for a double-view combined image 73 displayed on a screen 60 (only a part of the screen and the double-view combined image are shown), the vertical strip parallax barrier 80 performs view separation on the double-view combined image 73 at a plurality of optimal viewing positions V0, V1 (only four optimal viewing positions are shown, and a distance LV between the two optimal viewing positions V0, V1 is the average interpupillary distance (IPD)) on the optimal viewing distance Z0. Therefore, a single-view image is individually presented at the optimal viewing positions V0, V1, and the separated single-view image is characterized in having a half-screen resolution. FIG. 11 is a schematic view of a half-screen left-view image presented at the optimal viewing position V0. The half-screen left-view image
      ∑          i      =      0              M      -      1        ⁢            ∑              n        =        0                              int          ⁡                      (                          N              /              2                        )                          -        1              ⁢          V      0              i        ,                  2          ⁢          n                    is formed by the even-numbered columns of images V0i,2n of the left-view image 71. FIG. 12 is a schematic view of a half-screen right-view image presented at the optimal viewing position V1. The half-screen right-view image
      ∑          i      =      0              M      -      1        ⁢            ∑              n        =        0                              int          ⁡                      (                          N              /              2                        )                          -        1              ⁢          V      1              i        ,                              2            ⁢            n                    +          1                    is formed by the odd-numbered columns of images V1i,2n+1 of the right-view image 72.
Therefore, regarding the multi-view image having the number of views greater than 2, when the number of views is larger, the resolution of the displayed 3D image is reduced. For example, regarding a four-view image, the resolution of the separated single-view images is reduced to a quarter of the resolution of the full-screen image.